Synthesis of a plurality of diverse chemical compounds on a single substrate is known in the art. For example Fodor et al., U.S. Pat. No. 5,445,934 (incorporated herein by reference for all purposes) discloses forming an array by the steps of (i) disposing on a substrate a layer of linker molecules having photoremovable protecting groups; (ii) imagewise exposing the layer to radiation to activate selected regions; (iii) attaching a monomer with photoremovable protecting group to the activated regions and repeating the steps of activation and attachment until a plurality of polymer of the desired length and sequence are synthesized. The method of Fodor et al. has been used to form dense arrays of biological molecules of, for example, oligonucleotides, and is considered pioneering in the industry. The arrays formed according to the methods disclosed in Fodor et al. may be used, for example, in drug discovery, oligonucleotide sequencing, oligonucleotide sequence checking, and other applications.
While Fodor's above technique has met with substantial success, it would be desirable to provide additional and improved techniques for forming arrays of biological materials.
Other objects and advantages will become apparent from the following disclosure.